1. Field of the Invention
The present invention relates to an air inlet device for an engine air cleaner apparatus for a motor vehicle.
2. Description of the Prior Art
A motor vehicle""s engine combustion system depends on air. Because cooler air is denser, engines combust cooler air more efficiently than warmer air. Therefore, vehicles, especially heavy trucks, draw outside air into the vehicle""s air intake system for engine combustion. Along with outside air, however, particulates are also drawn into the air intake system with the outside air.
Ambient air enters the air intake system of a heavy duty truck, often through a port in the hood, and passes through a duct into an air cleaner. The air cleaner routes the air through a filter system that includes the air filter and any precleaners. The air filter traps particulates and keeps them from entering the engine combustion system.
The air filter must be kept relatively clean. A dirty or clogged air filter reduces the flow of air to the engine which decreases engine efficiency and can make the engine completely inoperable.
Where heavy snows are common, the air filter clogs easily. In engine air intake systems of heavy equipment, especially highway maintenance trucks and other vehicles used as snow plows, the air filter clogs with airborne snow. To avoid clogging, many vehicles have a snow valve to switch the inlet of the air cleaner from the normal air intake system""s port in the hood to an under the hood location during heavy snow conditions. By using the warmer under hood air, the snow valve can also enhance engine warm-up and maintain proper engine coolant operating temperature in extremely frigid conditions.
Prior art air intake systems from such vehicles often mount the snow valve separate from the air cleaner, which can be difficult to easily switch the valve from the normal air intake system to the under hood air intake. Furthermore, remote snow valves add cost to the system and are often difficult to package in the under hood space available.
U.S. Pat. No. 4,969,939 incorporates a snow valve integral with the air cleaner housing. The externally mounted snow valve operates through a cable connection with the vehicle operator""s compartment to switch the intake from outside air to under hood air under snow clogging conditions. The ""939 snow valve, however, has a large number of moving parts and is complicated both to operate and to assemble. The valve uses a flat valve cover plate externally mounted on a tubular housing. To define a flat mounting surface, circumferentially mounted legs of different sizes extend from the tubular air cleaner housing. The snow valve slides on a horizontal track between the flat valve cover plate and the air cleaner housing. A lever operating mechanism pivotally attached to the valve cover plate moves the valve by sliding the valve back and forth in its tracks with a rod welded to the valve. Sliding the ""939 snow valve horizontally back and forth generates high frictional loads. In addition, the operating mechanism and mounted legs of different sizes require extra parts to be assembled and aligned as well as an additional unique air cleaner housing mold tooling. Moreover, the valve design is not optimal for the lowered hood lines of the newer streamlined truck designs.
Therefore, one object of the invention is to produce an air inlet device or snow valve that is both easy to assemble and operate. The air inlet device would require fewer moving parts and generate less friction during movement. It is another object of the invention to produce an easily assembled snow valve that can fit a variety of air cleaner sizes and types. Another object is to design an air inlet device optimal for the lowered hood lines of the newer streamlined truck designs. Another object is to maintain proper engine coolant temperature under extremely frigid operating conditions.
According to the invention, there is provided an inlet device or snow valve adapted to fit an air cleaner housing for a motor vehicle. The inlet device has an annular door with an open window. The annular door is adapted to fit in the housing at an outside air opening in the housing. The annular door preferably has a front face with an aperture and a sidewall transverse the front face.
The inlet device can be used in an air cleaner apparatus for a motor vehicle. The apparatus has a housing with a chamber defined by an outer wall extending circumferentially and an end wall transverse to the outer wall. The outer wall has an outside air opening extending through the outer wall for receiving a flow of outside air into the chamber. The annular door is attached to the housing by securing means. The rotation means rotate the window between first and second positions, wherein the first position occurs when outside air flows through the window and the outside air opening into the chamber and the second position occurs when the annular door prevents the flow of outside air from entering the chamber through the outside air opening.
Additional effects, features and advantages will be apparent in the written description that follows.